Stargate Atlantis: The Complete Fifth Season (and also the final season) is available for pre-order. It'll be out June 30, 2009.

Supernatural: The Complete Fourth Season is available for pre-order. No date yet for its release.

Fringe Season 1 is available for pre-order. No date for the release is available at this time.

Kings - Season One will be available later this year. (Shame NBC just decided to cancel the show instead of finding a new timeslot that would work better for it - if such a slot existed.)

Battlestar Galactica: Season 4.5 is available for preorder from Amazon.com.

No word yet when it will be released. (Probably late summer? To tie into the Caprica series, perhaps?)

Battlestar Galactica Season Three will be available March 25, 2008.

Battlestar Galactica: Season Three at Amazon.com (currently $38.99 - subject to change)

The Showtime original series, The Tudors, will be available on DVD January 8th, 2008.
The Tudors - Season 1

Here's the product description from Amazon.com:

Rumor has it that just before Christmas, you can pick up a copy of High School Musical 2! Disney apparently will be releasing the DVD on December 11th.

Pirates of the Caribbean - At World's End (Two-Disc Special Edition)

Releases on December 4, 2007.